Surface blackening phenomenon and formation mechanism in high-temperature annealed nickel-based superalloys
Bibliographic record
Abstract
Abstract Owing to stringent service conditions, nickel-based superalloys must meet exceptionally high surface quality standards. After cold rolling, these alloys can blacken during annealing, affecting appearance and performance. The surface-element distribution of GH4169 alloy annealed under hydrogen protection was analyzed via XPS, and reaction free-energy changes were calculated using thermodynamic software. The blackened surface contained oxides and carbides, primarily Cr2O3, Cr(OH)3, TiO2, Nb2O5, NbC, and free carbon. Residual water vapor in the protective hydrogen gas and rolling-oil remnants generated C, CO2, CO, and H2O, which then reacted with the alloy during high-temperature annealing to form a blackened layer. The selective oxidation of Cr, Nb, and Ti, along with the inward diffusion of carbon, leads to the compositional differences observed in the blackened layer. Lowering the protective gas dew point, improving rolling oil, and effective degreasing eliminated blackening.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".